Hdu3652 B-number详解

B-number

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 10866    Accepted Submission(s): 6455
 

Problem Description

A wqb-number, or B-number for short, is a non-negative integer whose decimal form contains the sub- string "13" and can be divided by 13. For example, 130 and 2613 are wqb-numbers, but 143 and 2639 are not. Your task is to calculate how many wqb-numbers from 1 to n for a given integer n.

Input

Process till EOF. In each line, there is one positive integer n(1 <= n <= 1000000000).

Output

Print each answer in a single line.

Sample Input

13

100

200

1000

Sample Output

1

1

2

2

   

 

此题思路：数位dp+记忆化搜索

好几个小时了，把能搜到的博客都看了，思路大体一样，还是感觉一知半解，打算等搞懂这道题写个详解...先开个坑，尽量早点填